ODROID-U3 with PX4FMU and PX4IOAR for SLAM

Hi

I am using a Parrot AR.Drone with PX4FMU and PX4IAOR. In addition I am using a ODROID-U3 with Structure sensor for SLAM. The ODROID-U3 performs onboard computing

I would like to ask if its necessary to connect the board with the flight controller
There is a tutorial for connecting the Pixhawk with ODROID-U3 over MAVLink. What is the uasge of the connection

kindly guide

Can I connect it from the GPIO (I2C connections) to the UART port on the PX4IOAR